1. Field of the Invention
The present invention relates to an endoscope including a flexible pliable tube in an insertion portion wherein at least one slender tube element is installed in this pliable tube, and a manufacturing method therefor.
2. Description of Related Art
Hitherto, medical endoscopes have been used widely, wherein organs in body cavities, etc., can be observed by inserting slender insertion portions in the body cavities and, if necessary, various therapeutic treatments can be performed using endo-therapy products inserted through endo-therapy product channels.
In particular, regarding the endoscope used in a medical field, by inserting the insertion portion in the body cavity, observation of organs, etc., is performed and various therapies and treatments are performed using endo-therapy products inserted through the endo-therapy product channel of the endoscope. Consequently, when an endoscope and endo-therapy product used once have been reused for other patients, it has been necessary to perform cleaning and disinfection after an inspection and treatment has been completed for reasons of necessity to prevent cross infection between patients through the endoscope and endo-therapy product.
In recent years, inexpensive autoclave sterilization (high-pressure steam sterilization) has become the mainstream of the disinfection and sterilization treatments of medical equipment, wherein no complicated operation attends, it is possible to use immediately after sterilization, and a running cost is low.
Consequently, in Japanese Unexamined Patent Application Publication No. 10-276968, an endoscope is disclosed, in which in order that a built-in tube does not contract during high-pressure steam sterilization with an autoclave and that an adequate sterilization treatment can be performed repeatedly, a tube made of fluororesin is used as a pliable tube built in for passing through a fluid, endo-therapy product, or the like, and the tube made of fluororesin is subjected to an annealing treatment before being incorporated into the endoscope.
However, the aforementioned tube is difficult to contract completely during the annealing treatment because of, for example, differences in material properties, such as thermal deformation temperatures and glass transition temperatures, differences in structures, such as the material, which may be a solid material or foam, constituting the tube, and differences in manufacturing methods. That is, for example, some tubes do not contract unless very high temperature is applied, and some tubes need long-duration annealing. Regarding these tubes, even when the annealing treatment was performed at a temperature slightly higher than that in the high-pressure steam sterilization step, sometimes, the tube shrank more than the condition desired because the high-pressure steam sterilization step was performed repeatedly over the long term.
Furthermore, when the tube shrank more than the condition desired, it was feared that an excessive force was applied to the connection portions at both ends of the tube and, therefore, breakage was brought about, or the tube was pulled in the insertion portion and, therefore, inconvenience was brought about in the shape of a curve of a curved portion installed at the tip side of the insertion portion.
The present invention was made in consideration of the aforementioned circumstances. Accordingly, it is an object of the present invention to provide an endoscope in which inconvenience brought about due to contraction of a tube element built in an insertion portion during high-pressure steam sterilization is prevented.